Valve stem seals having resilient seal bodies supported within rigid cylindrical casings are available in many designs and configurations. Most designs address the efficiency of the actual sealing lip portions of the seals which determine a controlled flow of oil between the seal lip and the valve stem.
Generally, the rigid cylindrical casing is supported on a valve stem guide with the inside diameter of the casing frictionally engaging the outside diameter of the guide. Previous designs have utilized tangs on the casing to grip the exterior surface of the guide to resist removal of the valve stem seal from the valve guide. However, the tangs of the prior art do not accommodate wide tolerance variations that are typically encountered with manufacturing valve stem guides. Thus, the tangs of the prior art require more precise valve stem guides to ensure that the tangs will adequately grab the outer diameter of the guide and resist pulling off of the seal. In addition, the tangs in cylindrical casings of the previous designs tend to have engagement along an entire edge of the tang that creates difficulties for aligning the valve stem seal relative to the valve guide and negatively impacts the resistance to removal.